Characterization of the New Open Surface Recirculating Water Tunnel Facility at the Indian Institute of Technology Kharagpur

The present study aims to characterize the free stream flow of the newly installed recirculating water tunnel facility in the BIAHR Laboratory at the Indian Institute of Technology Kharagpur. This tunnel can operate at speeds ranging from 0.05 m/s to 0.40 m/s in the test section. The dimension of the test section is 400 × 400 × 1500 mm3 in width, depth, and length respectively. An acoustic Doppler velocimetry is used to measure the instantaneous velocity in the test section at the frequency of 10 Hz with a measured accuracy of ± 1%. The flow velocity in the test section is found to vary linearly with motor speed, and the turbulence level decreases on increasing the motor speed. The average temporal stability in the tunnel is found to be less than 1%, and the maximum possible deviation in the spatial uniformity is less than ± 1.35%. Furthermore, the free stream turbulence intensity characteristics in the test section are determined at different operating velocities.